Castiel believes he is the new God and becomes obsessed with power. Sam, Dean, and Bobby try to find a way to stop him before he explodes with power, even if that means talking to Death himself.
The leviathans destroy Castiel's body and break loose. Now Sam, Dean, and Bobby have to track them all down. Meanwhile, Sam is beginning to struggle with what is real and what is a hallucination.
An estranged Sam and Dean reunite to solve a curious case in the most psychic town in America, but it's far from happy families for the Winchester brothers.
Sam and Dean are stumped. Somehow, a group of children's personal fears are becoming a reality and killing off a parent that each child has a certain hatred for.
Sam and Dean discover that Frank's hard drive, containing everything on the leviathans, is now in Dick's company building. To retrieve it, they ask for help from one of the employees, a young computer hacker.
Sam and Dean have possession of a Word of God, but are unable to read it. They find a young prophet that can help, but unfortunately, the angels and leviathans are after him, too.
To officially kill the leviathans, Sam and Dean need the blood of an Alpha. But Dick knows what the Winchesters are up to and sends his men after them.
Sam and Dean make a plan to storm Dick's company building and kill him once and for all, with help from Castiel and Meg. Providing Bobby doesn't get to Dick first.